The Celtics are down, Game 5 was a devastating loss, but they are not done yet

Game 5 against the Bucks was arguably the Celtics' most crushing loss since Game 7 of the 2010 NBA Finals.Jim Davis/Globe Staff

Following the Celtics’ stirring victory over the Bucks in Game 4 of the Eastern Conference semifinals, which happened Monday night and suddenly feels like a month ago, I concluded my column like this:

“Don’t know about you, but I’m not planning on doubting [the Celtics] again until they’re done.”

Three days, one game, and one tongue-swallowing collapse later, and you know what? I am not ready to eat those words, much like how the Bucks’ Jrue Holiday made Marcus Smart eat the basketball on a hero-ball layup attempt late in the fourth quarter.

I’m standing by it. The Celtics are down, and they are devastated. But they are not done yet.

Oh, make no mistake, Wednesday night’s loss — a 110-107 Game 5 defeat in which pretty much everything that could have gone wrong did in the final minute and a half — was devastating. There’s no question about that.

I’ll spare you the full autopsy since chances are the assorted regressions, poor decisions, and affronts to winning basketball in the final couple of minutes have probably been replaying in your hungover head since waking up Thursday morning and realizing, no, it wasn’t all a bad dream.

Let’s just note for accounting purposes that the Celtics led by 14 points with 10½ minutes remaining and 6 with 2:11 left after what felt like an exclamation-point-on-the-victory follow-up slam by Al Horford.

AL HORFORD TURNS THE CLOCK BACK AGAIN ⏱

CLUTCH PUTBACK SLAM pic.twitter.com/39dP1Sw5ZH

— Bleacher Report (@BleacherReport) May 12, 2022

And they lost. They lost because Smart, who played a terrific game right up until the bitter end, made a sequence of poor decisions down the stretch. The farther we get away from it, the more stunning it is in retrospect that Smart had the discipline to pass up the potential last shot and feed Jayson Tatum for the winning basket in Game 1 against the Nets.

They lost because every youth basketball coach’s recurring plea to box out too often went unheeded by these professionals, to the point that Bobby Portis’s go-ahead put-back of a missed free throw with 11.4 seconds left felt awfully close to inevitable.

They lost because Tatum settled when he should have attacked, Jaylen Brown and Grant Williams got lost on defensive switches, and they lost because Holiday, Giannis Antetokounmpo, and these champion Bucks have too much experience and spirit to ever go quietly.

The Celtics should have won. Practically had it won. And they lost. It was arguably the franchise’s most crushing loss since Game 7 of the 2010 NBA Finals, which is kind of remarkable given that they’ve lost four times in the Eastern Conference finals since then.

But if you’re ready to give in to doubt, or to give up on them entirely, ask yourself one question about these 2021-22 Celtics: What has been their greatest attribute this season?

I’d answer that it’s their uncommon resilience, and I think it’s an easy answer. They were a mess for the first couple of months, winning just 18 of their first 39 games. But Brad Stevens repaired the roster, rookie coach Ime Udoka stayed on message, the players fought back against their flaws individually and collectively, and they roared up the standings in the second half to the No. 2 seed, then wiped out Kevin Durant and the Nets in a first-round sweep.

This team knows how to handle adversity, self-inflicted and otherwise, and now they face their toughest challenge yet. Rather than taking a 3-2 lead back to Milwaukee for Game 6, they’ll play Friday night with their season at stake. The degree of difficulty is so much steeper now. They must deal with a raucous crowd, the likelihood that Antetokounmpo will get every call, and a bloodthirsty Bucks team that knows how to put an abrupt end to its opponent’s greatest aspirations.

But not much has come easy for the Celtics this season, especially at the beginning. And yet they stuck together, became unified rather than splintered, developed an us-against-the-world mentality, and became the most admirable and enjoyable Celtics team since Isaiah Thomas and that cast of misfits and underdogs gave the Cavaliers a fight in the 2017 conference finals.

How will Ime Udoka and the Celtics respond in Game 6?Matthew J Lee/Globe staff

They can overcome the devastation of Game 5. They know what they have to do: share the basketball, and don’t devolve into slow-it-down isolation ball when they have a lead. Eliminate the careless turnovers (can we acknowledge Brown, for all of his strengths, remains a terrible passer?) and value the possession of the basketball. And for heaven’s sake, stop griping at the officials — a longtime Tatum habit that has become contagious — and get back on defense. Boxing out and not N’Keal Harry-ing the rebounds you do get a hand on would also be helpful.

The Bucks are an exceptional foe, similar to the Celtics in skill and structure, but with a champion’s pedigree. Yet the Celtics do not fear them. They coulda/shoulda won Game 3 in Milwaukee. They bounced back with a fantastic win in Game 4. They can prevail there again.

It’s going to be difficult, the most difficult challenge they have faced. But this is a team that turned its season around three months ago when it would have been so easy to write them off. It’s understandable to have doubts about them now, after Wednesday’s debacle. Just don’t give up on them. Because for all of those flaws and frustrations fresh in our minds, you know they’re not going to give up on themselves.